MYSQL 查询和删除重复记录的方法很多,下面就为您介绍几种最常用的 MYSQL 查询和删除重复记录的方法,希望对您查询和删除重复数据方面能有所帮助。

SQL重复记录查询的几种方法:

1. 查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断

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select * from people
where peopleId
in (select peopleId from people
group by peopleId
having count(peopleId) > 1)

2. 删除表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断,只留有 rowid 最小的记录

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delete from people 
where peopleId
in (select peopleId from people
group by peopleId
having count(peopleId) > 1)
and rowid not in (
select min(rowid) from people
group by peopleId
having count(peopleId)>1)

3. 查找表中多余的重复记录(多个字段)

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select * from vitae a
where (a.peopleId,a.seq)
in (select peopleId,seq from vitae
group by peopleId,seq
having count(*) > 1)

4. 删除表中多余的重复记录(多个字段),只留有 rowid 最小的记录

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delete from vitae a
where (a.peopleId,a.seq)
in (select peopleId,seq from vitae
group by peopleId,seq
having count(*) > 1)
and rowid not in (
select min(rowid) from vitae
group by peopleId,seq having count(*)>1)

5. 查找表中多余的重复记录(多个字段),不包含 rowid 最小的记录

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select * from vitae a
where (a.peopleId,a.seq)
in (select peopleId,seq from vitae
group by peopleId,seq
having count(*) > 1)
and rowid not in (
select min(rowid) from vitae
group by peopleId,seq
having count(*)>1)

以上 SQL 记录重复数据查询和删除方法,希望能够帮助你。


本文地址 http://ihongqiqu.com/2016/11/24/repeat-sql-data/ 作者为 Zhenguo

author:Zhenguo
Author: Zhenguo      Blog: http://ihongqiqu.com/     Email: jinzhenguo1990@gmail.com
I have almost 6 years of Android application development experience and have a keen interested in the latest emerging technologies. I use my spare time to turn my experience, ideas and love for Android tech into informative articles, tutorials and more in hope to help others and learn more.
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